1. Field of the Invention
This invention relates to a process for producing a belt used in electrophotographic image forming apparatus (hereinafter also an “electrophotographic belt”. The electrophotographic belt includes as examples thereof an intermediate transfer belt which temporarily holds thereon toner images transferred from an image bearing member and from which the toner images are transferred to a transfer material.
2. Description of the Related Art
As a construction of the electrophotographic belt such as the intermediate transfer belt, a belt is known which has a multi-layer structure having a base material with a good strength and a protective layer for improving cleanability and wear resistance.
Here, as the protective layer, a protective layer containing a resin (hereinafter also a “resinous protective layer”) is commonly used in order to satisfy the flexibility that is required for the belt. In this case, it is proposed to add various fillers for the purposes of controlling resistivity and surface roughness of the resinous protective layer and reinforcing the same. However, the addition of fillers to the resinous protective layer may make the resinous protective layer brittle, depending on the amount in their addition. To resolve such a problem, Japanese Patent Laid-open Application No. 2000-255817 discloses a conductive belt having a conductive layer and a protective layer formed on the conductive layer, said protective layer comprising a conductive filler and said conductive filler being gradually dispersed in the protective layer so that the content of a conductive filler increases from the conductive layer towards the surface side (gradient in the thickness direction). Then, this patent document discloses that a protective layer more containing the filler on the surface side can be produced with ease by centrifugal molding.
The present inventor has made studies on methods for producing by centrifugal molding a protective layer more containing a filler toward its surface side. As a result, he has found it difficult for such methods to reduce production cost of belts, because the employment of centrifugal molding requires a high cost for its equipment and also a long molding process.